Bacterial Type IV pili are essential for host colonization and virulence for many Gram negative bacteria, and may also play a role in pathogenesis for some Gram positive bacteria. Type IV pili extend from the bacterial surface and mediate specific adherence to biotic and abiotic surfaces. The pili binding domain responsible for this binding is encoded within a 12-17 disulfide loop region located in the C-terminal region of the protein, and synthetic peptides containing this region only, e.g., a disulfide-loop peptide composed of residues 128-144 from the Pseudomonas aeruginosa Type IV pilin, have been shown to bind to biotic and abiotic surfaces.
The present inventors and colleagues have recently shown that pilin-derived protein nanotubes (PNTs) bind to stainless steel with high affinity, and the binding event was shown to be C-terminal tip-associated through competitive inhibition of PNT binding by synthetic peptides corresponding to the Type IV pilin peptide binding domains. (Yu, B. et al., J. Bionanoscience, 1:73-83 (2007). It was then further demonstrated by the present inventors and colleagues that pilin peptides derived from the C-terminal receptor binding domain, when bound to abiotic surfaces such as stainless steel, tin, aluminum, titanium, chromium, plastic, glass, silicate, ceramics, and mixtures thereof, were able to inhibit bacterial biofilm formation on the coated surfaces (U.S. 20080287367).
It has now been discovered that binding of synthetic pilin peptide containing a disulfide loop derived from the C-terminal receptor binding protein of Type IV P. aeruginosa (T4P) pilin to some metals significantly enhances certain surface properties of the metal, i.e., independent of biofilm formation, and in some metals alters the electronic properties of the surfaces in ways that can be exploited, for example, in biosensor applications.